Hi there, and nice choice of car
Sounds like an unexpected bonus finding that your car has been mildly fettled by a highly reputable Alfa specialist. I'd be chuffed to bits if I found something like that.
Did you buy the car from a dealer or a private sale? Was there no other paperwork to suggest what work had been carried out on the car?
From what I can gather, TBi models can be vastly improved by having a remap done, especially in the fuel economy department (okay don't expect miracles but a definite improvement is possible). The engine appears to be very tuneable and is now very similar in spec to the ones found in the Giulietta Cloverleaf and 4C.
My only concern would be the life of the M32 gearbox and so I'd be keen to speak to AHM or Alfatune about how you can get the most out of it and avoid a failure.
If the figures are accurate the power should now be upwards of 240bhp and more importantly, the torque could be in excess of 300lb/ft!!! (hence my concerns about the gearbox). You will have a seriously rapid car indeed.
As far as the insurance side of things is concerned, a reputable site like this can't be seen to be condoning non-disclosure of material facts like a remap to insurers but as an ex-broker of 20 years myself with vast experience of the industry, I know what I'd do
Also, a remap purely designed for improvement in fuelling and/or economy is still a remap and should be disclosed.
As I say though, I know what approach I'd take.
Anyway, congrats on what looks like a superb purchase.